Scientists researching the causes and effects of hypoxia in Green Bay, part of Lake Michigan, Wisc., have been awarded $348,037 for the first year of an anticipated four-year $1,367,300 project through NOAA's Coastal Hypoxia Research Program. Hypoxia within Green Bay has been a problem for decades, and recent evidence suggests that it may be worsening, with the potential for "dead zones" and fish kills to become both more frequent and more extensive with a changing climate.
Hypoxia is a condition in which dissolved oxygen levels in water become too low to support most life. While hypoxia can occur naturally, it is often caused by excess nutrients from human activities such as agriculture and urban stormwater runoff, which stimulate algal blooms. These blooms of algae decompose through the action of bacteria that deplete oxygen from the water, and in the process, negatively affect the growth, reproduction, and survival of organisms exposed to the low oxygen conditions.
Green Bay is particularly vulnerable to hypoxia because one-third of the watershed of Lake Michigan drains into it, and it receives approximately one-third of the total amount of nutrients draining into the lake.
A team of scientists from within the University of Wisconsin system (Milwaukee, Green Bay and Madison), the Green Bay Metropolitan Sewerage District, and the Wisconsin Department of Natural Resources will evaluate watershed sources of nutrients, lake water stratification (the layering of the water by temperature that prevents dissolved oxygen from reaching bottom waters) and summertime wind conditions to develop a predictive model of potential changes in hypoxia relative to land use change and future climate change.
"These results will help us identify acceptable limits for nutrient levels in the water so we can begin to reduce hypoxia in Green Bay," said Nicole Clayton, Wisconsin department of natural resources, impaired waters and total maximum daily load coordinator.
"This project is an excellent example of NOAA's efforts to provide actionable information to managers for ecosystem based management," said Robert Magnien, Ph.D., director of NOAA's Center for Sponsored Coastal Ocean Research. "The complexity of linking multiple processes in the watershed with those in Great Lakes and coastal waters demand new state-of-the art ecological forecasting tools that also incorporate climate change."
NOAA's mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources.